International Journal of Experimental Dental Science

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VOLUME 10 , ISSUE 1 ( January-June, 2021 ) > List of Articles


Evaluation of Smear Layer after Er:YAG Laser Irradiation in Middle and Apical Third of Mesial Root Canals: A Comparative SEM Investigation

Evrykleia Kourti, Ourania Pantelidou-Papadopoulou, Kosmas Tolidis, Dimitris Strakas

Keywords : Er:YAG laser, Mesial root canals, Molars, Smear layer removal

Citation Information : Kourti E, Pantelidou-Papadopoulou O, Tolidis K, Strakas D. Evaluation of Smear Layer after Er:YAG Laser Irradiation in Middle and Apical Third of Mesial Root Canals: A Comparative SEM Investigation. Int J Experiment Dent Sci 2021; 10 (1):14-18.

DOI: 10.5005/jp-journals-10029-1221

License: CC BY-NC 4.0

Published Online: 11-08-2021

Copyright Statement:  Copyright © 2021; The Author(s).


Aim and objective: This ex vivo study evaluated the efficiency of an Er:YAG laser (2940 nm) at different pulse energy levels to remove the smear layer with or without chelators from the middle and apical third of mesial roots. Materials and methods: Thirty-four mesial root canals of first mandibular molars (type II Vertucci) were divided into four groups of eight teeth each. Each group consisted of two subgroups each (A and B), regarding the irrigation protocol. In subgroup A, teeth were rinsed only by distilled water whereas, in subgroup B, teeth were rinsed by 5 mL 17% EDTA for 60 seconds, 5 mL 5% NaOCL, and 5 mL distilled water. The rest two teeth were used as control groups. After coronal access, all teeth were instrumented up to size F3 (30/0.09) and, then, the experimental groups were irradiated by an Er:YAG laser (2940 nm). Four different pulse energy values were tested, namely 30, 50, 70, and 80 mJ to irradiate the roots in group I, group II, group III, and group IV, respectively. The control group (n = 2) was instrumented and rinsed as experimental groups (subgroup B) but not irradiated. Teeth were observed under SEM. Results were statistically analyzed with the Kruskal–Wallis test. Results: There is a statistically significant difference between groups irrigated with chelators and groups with distilled water before laser irradiation in the apical third. Group IB (0.75 W) showed a statistically significant outcome in the apical part. The results showed no statistical difference between subgroup B and the control group. Conclusion: The presence of a chelating factor may play an important role in the laser mechanism of smear layer removal from the apical part of narrow and curved root canals.

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